Earlier Spring Blooms Reflect Warming

Flowering Plants Bloom Earlier With Warming

One of the clearest measures of global warming is right outside your window: earlier blooming and budding plants in the spring.

A nationwide citizen science effort to chart the blooming of key plants each spring and even in the autumn is now beginning to reveal clear warming trends in the U.S.

Project BudBurst scientists are getting reports that common lilac, red maples, Virginia bluebells and other popular ornamental plants on their "10 Most Wanted" list are waking up earlier in the spring than ever -- a sign that the climate is heating up.

"We're seeing that the data show that spring is advancing," said Sandra Henderson of the University Corporation for Atmospheric Research (UCAR), which oversees Project BudBurst.

Although this is only the fourth year of the project, the resulting data has now been compared to a 50-year record of when plants bloom and leaves bud in the Chicago area, as compiled in the book "Plants of the Chicago Region" by Floyd Swink and Gerould Wilhelm.

The book has budding and blooming information from the 1950s through 1994, reports Kayri Havens of the Chicago Botanic Garden. There are 15 species of plants that have data from both Project BudBurst and the book.

"Seven of 15 species had a first bloom earlier in one or more of the last three years than ever seen by Swink and Wilhelm -- both avid field botanists -- in the past 50 years," Havens explained.

The seven species that advanced are forsythia (April 25 to April 1), spiderwort (May 14 to May 3), dogtooth violet (April 6 to April 1), red maple (March 20 to March 6), mayapple (May 1 to April 26), lilac (May 3 to April 16) and black locust (May 9 to April 20).

Project BudBurst's new "10 Most Wanted" plants overlap with that list as well, including forsythia, spiderwort, mayapple and red maple. The rest of the "10 Most Wanted" are trees, shrubs or other flowering ornamental or native plants which are very widespread in North America.

Pictures and descriptions of the plants can be found at the Project BudBurst website.

"It helps to have this targeted collection," said Henderson, because some citizen scientists prefer to focus their efforts. However, Project BudBurst welcomes data on as many flowing plants as people are willing to monitor, she said.

All the instructions for participating, including a geolocator so participants can report their whereabouts, are available at the project website. An application that allows citizen scientists to report their findings on their cell phones may soon be available, Henderson said.

"UCLA is working on a mobile phone application to do it," Henderson said. The application will allow users to quickly send in photos documenting what a plant in a particular location is doing on a given day.

"Project BudBurst and other citizen science campaigns is actually empowering," said Henderson. "We want people to be outside in a meaningful way."